Selector release circuit



SELECTOR RELEASE CIRCUIT Aug. 15, 1939 3 Sheets-Sheet 1 Filed Sept. 11, 1937 FIG! C. W KEC/(LER- ARAYNSFORD BY 696. M

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Aug. 15, 1939 c. w. KECKLER ET AL SELECTOR RELEASE CIRCUIT s Sheets-Sheet 2 Filed Sept. 11, 1937 Ira CW/(ECKLER A. RAY/VSFORD IN VE N TORS A TTORNE V Aug. 15, 1939 c. w. K-ECKLER El AL 2,169,389

SELECTOR RELEASE CIRCUIT Filed Sept. 11, 193'? a Sheets-Sheet s C. W KEC/(LER A. RAYNSFORD H M w M: M Emmi m l v w r 2 5% 7 45m: #2:- TE

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A TTORNEY Patented Aug. 15, 1939 UNITED STATES PATENT OFFICE SELECTOR RELEASE CIRCUIT Charles W. Keckler, Summit, and Arthur Raynsford, Bergenfield, N. J., assignors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application September 11, 1937, Serial No. 163,376

7 Claims. (01. 17918) This invention relates to telephone systems and spective patent drawings and where duplications. more particularly to such systems in which telewould occur a suffix A has been added to distinphone connections are normally under the conguish between them for the purposes of the prestrol of the calling subscriber, and has for its out disclosure.

5 object to facilitate the release of the called sub- Referring first to the non-coin circuits, after scriber from such connections. the connection has been set up as described in In the panel type telephone system, telephone the above patents, a talking connection is esoonnections are normally held by the calling tablished which includes the district selector of subscriber and the restoration of the receiver of Fig. 1 and the o-ffice, incoming and final selectors the called subscriber to the switchhook is inefof Fig. 2. The connection consists of three cir- 10 fective to free that subscribers line for other cuits established with the various sequence calls. Various means have been devised for placswitches in talking position. The talking position ing the release under the control of the called for sequence switch 990 of the district selector is subscriber in the step-by-step telephone system, either position It or I4 and in either of these but heretofore no such means has been devised positions the calling subscriber at substation E00 15 for the panel system. controls a circuit extending from battery through In accordance with the present invention, the lower left winding of repeating coil 63L conmeans is provided, common toaplurality of panel tacts of cam Bil, winding of supervisory relay type district selectors, and responsive to release GIG, outer lower back contact of relay 1H5, brush by the calledsubscriber for measuring a time in- 33I, terminal 332, through substation 500, ter- 20 terval and transmitting a signal to the district minal 333, brush 334, upper back contact of relay selector connected with the called line, which 3I6, contacts of cam 6I5, upper left winding of signal is effective in the case of non-coin district repeating coil 63l, to ground. Relay tilt is: operselectors to release the district selector and the ated when this circuit is established and cioses connection, and in the case of coin district sea circuit from ground over the lower contacts of 25 lectors is effective to advance the district seleccam 632, front contact of relay 6&6, resistance tor sequence switch to a position in which the 634, through the winding of relay 35I to battery. outgoing end of the connection is released and a Relays 35 I and Mt, therefore, remain operated signal is transmitted to the calling line. under the control of the calling subscriber The invention will be more clearly understood throughout conversation. 30 from a consideration of the following description With the incoming selector sequence switch taken in connection with the drawings in which I0--A in talking position I6 and the final se- Fig. 1 shows a portion of a non-coin type district lector sequence switch 2520 in talking position I3, selector and the common release control means; the called subscriber at substation 286) controls Fig. 2 shows a portion of a coin district seleca circuit which may be traced from battery 35 tor; and through the lower right winding of repeating coil Fig. 3 shOWs portions of office, incoming and I38, winding of supervisory relay I48, contacts final selectors for completing a connection to a of cam I49, brush I31 and its associated tercalled subscriber. minal, contacts of cam 252, brush 255 and its 40 These drawings are skeletonized from complete associated terminal, through the substation 280, 40 circuits to show merely the talking circuit in talkbrush 254, contacts of cam 202, brush I39--A, ing positions, the holding circuits and the circontacts of cam I34, upper right winding of recuits involved in the release of the connection. peating coil I38 to ground. Relay I48 is oper- For complete circuits and descriptions reference ated in this circuit and holds relay H0 operated may be made to the following Patents 1,601,058, in a circuit from battery through resistance I29, 45 granted to C. H. Berry, September 28, 1926, for left winding of relay H0, front contact of relay the Oflice selector; 1,658,829, granted to C. H. I48, contacts of cam IOBA to ground. Relays Berry, February 14, 1928, for the Incoming and H0 and I48, therefore, remain operated throughfinal selectors; Patents 1,823,040, granted to A. E. out the conversation under the control of the q 50 Hague, September 15, 1931, for the Coin district called subscriber. 50 selector and 1,855,598, granted to W. W. Carpen- With relay H0 operated, an intermediate cirter et al. April 26, 1932, for the Noncoin district cult is closed, with the office selector sequence selector. With the exception of the release conswitch I08 in talking position 8, which may be trol circuit shown under the broken line in Fig. 1, traced from battery through the upper windings reference numerals have been taken from the reof relay I35 and coil I36, contacts of cam I I5,

right front contact of relay H0, contacts of cam I40-A, lower left winding of repeating coil [30, ring brush of the ofiice selector, contacts of cam ISLterminal I06, brush 625, contacts of cam 624, lower right winding of repeating coil 63I, through the winding of polarized relay 30I, upper right winding of repeating coil 63I, contacts of cam 622, brush 62I, terminal I05, contacts of cam I04, tip brush of the office selector, contacts of earn 539, upper left winding of repeating coil I38, contacts of cam I31, left front contact of relay IIO, contacts of cam II'I, lower windings of coil I36 and relay I 35, contacts of cam MI, back contact of relay I06-A to ground overthe contacts of cam H3. The direction of current flow in this circuit is such that polarized relay 30I is operated, closing a circuit from ground over the lower right contact of cam 632, the upper contact of cam 635, front contact of relay 30I, right contacts of cam 6I0, to interrupter 322. When this interrupter closes its right contact the circuit is extended to the winding of relay 302 and battery. Relay 302 operates and locks over its left contact and the left contact of cam 6I8 to the ground controlled by relay 30I. With relay 302 operated, the closure of the left contact of interrupter 322 extends ground over the right front contact of relay 302, left contacts of cam 602, winding of relay 32I and battery. Relay 32I controls the charge on the message register of the calling subscriber in the manner described in the Carpenter et a1. patent. V

Speech currents also traverse these paths being ransrnitted from one to another by the repeating coils 63I and I38.

With the district selector in talking position, the calling subscribers line is marked busy and the cut-off relay I02 is held operated by battery through resistance 3| 3, contacts of cam 608, inner lower back contact of relay 3I6, brush 326, terminal 327, Winding of cut-off relay I02 to ground. The office selector is held busy by means of a circuit extending from ground over the lower right and upper contacts of cam 632, sleeve brush 633, sleeve terminal II4, left contacts of cam I30, left front contact and winding of relay I02, contacts of cam I M, right windingof relay I02 to battery, relay IOI having been operated previously. The outgoing trunk is also held busy by ground from the district selector extended .over the upper contacts of cam I30 to sleeve brush I40.

The final selector is held busy by means of ground connected over the contacts of cam I24 to brush I32 which supplies locking ground for relay 208, previously operated, whose locking circuit extends from battery through the winding of relay 208, contacts of cam 209, front contact of relay 208, contacts of cam 2 to conductor 2I4 connecting with the terminal engaged by brush I32. The called subscribers line is held busy by means of ground over the contact of cam 225, resistance 246, contact of cam 24I, brush 234, to thewinding of cut-off relay 236 and battery. It may be noted that in this case the calling office supplies ground to the cut-off relay, while'the called office supplies battery to the cut-off relay.

At the termination of conversation, the restoration'of the receiver to the switchhook by the called subscriber at substation 286 releases relay IE3 in turn releasing relay I I0. The release of relay IIO reverses'the connection of relay I35 to the incoming side of the repeating coil I 38, the connection now extending from battery through the upper windings of relay I35 and coil I 36, contacts of cam H5, contacts of cam I 25, left 'back contact of relay IIO to cam I 31 and thence as previously traced to the right armature of relay H0 and over the back contact thereof, contacts of cam I46, lower windings of coil I36 and relay I35 to ground as above traced. As a consequence, relay 30I of the district selector releases, in turn releasing relay 302. Formerly the circuits remained in this condition until the calling subscriber restored his receiver to the switchhook.

In accordance with the present invention, when relay NI releases, a circuit is closed from ground over the lower right contact of cam 632, the upper contact of cam 635, back contact of cam 30L outer right contact of relay 32I to conductor I0 and through resistance I I to the uppermost armature of relay I2. Relay I2 is operated and released at measured intervals by the operation of the interrupter I3, and. at its next operation extends ground from conductor I0 over its uppermost armature to the winding of relay I4. Relay I4 in turn operates relay I5, which provides a holding circuit for relay I4 over conductor I0 independent of relay I2. A measured interval after the operation of relay I2, when interrupter I3 closes its left contact, a, circuit is closed for relay I6 which closes a circuit from ground at the outer right front contact of relay I5 over the uppermost armature of relay I6 to the winding of relay I7 and battery. Relay I1 in operating connects groundto relay I8 and meter I9 for recording the fact. that the release control circuit has been used. Relay I I also connectsthe conductor I0 to conductor 20.

The connection of conductor I0 to conductor 20 completes a circuit from ground on these con ductors over the contacts of cam 648, through the lower winding of relay 3I6 to battery. Relay 3I6 in operating locks in a circuit from battery through its upper winding and inner upper front contact to ground over the upper left and lower right contacts of cam 603. Relay 3I6 also opens the incoming end of the; talking circuit, releasing relay 6I6, and when interrupter 328 opens, releasing relay 35L Relay 3I6 also closes acircuit from ground over cam 603, over the upper front contacts of relay 3 I 6, upper contacts of cam 60I, to the winding of sequence switch magnet 600 and battery advancing the sequence switch to position I1.

With sequence switch 600 in position I'I, relay 302 is reoperated in a circuit from battery through the winding of relay 302, lower contacts of cam 60I, contacts of cam 648, back contact of relay 35I, over the contacts of interrupter 328. Relay 302 locks under the control of the line finder commutator (not shown) and closes a circuit for sequence switch 600 from battery through the winding of sequence switch magnet 600, lower contacts of cam 602, right contact of relay 302 to ground over the right contacts of cam 603. Sequence switch 600 advances in this circuit to position I8 where the line finder switch and district selector switch are restored to normal, resulting in the advance of sequence switch 600 to position i. For the details of this operation, reference is made to the Carpenter et a1. patent above identified.

The advance of district selector sequence switch 600 from position I6 opens the ground connected to sleeve brush 639, thereby releasing relay I02 in the office selector circuit and closing a circuit from ground over the contactsof cam I09, left back contact of relay I02, contacts of cam I23, winding of sequencev switch magnet I 08 and battery. Sequence switch I08 advances from position 8 opening the talking circuit, and disconnecting busy ground fro-m brush I40. With sequence switch I08 in position 9 the oifice selector switch is restored to normal, after which sequence switch I08 is advanced to position I which is a second normal position. For the details of these operations, reference is made to the Berry Patent 1,601,058 above-mentioned.

The advance of sequence switch 600 from position I6 opens the circuit of relay 30I permitting relay I 35 of the incoming selector to release. With relay I35 released, a circuit is closed from ground over the back contact of relay I35, contacts of cam I09-A, winding of relay -I00A to battery. Relay I06A in operating closes a circuit from battery through the winding of sequence switch magnet I00-A, contacts of cam I i2, front contact of relay I03Ato ground over the contacts of cam II3. Sequence switch I00-A advances in this circuit to position I8 where the incoming selector switch is' restored to normal, after which the sequence switch is restored to position I. The advance of sequence switch HIL -A from position I! disconnects ground from brush I32, opening the locking circuit of relay 208 which releases, closinga circuit from ground over its back contact, contacts of cam 223 to the winding of sequence switch magnet 200 and battery, advancing the sequence switch toposition 25. From this position sequence switch 200 is advanced under control of an interrupter (not shown) to position I8 where the final selector switch is restored to normal, thereby advancing sequence switch 200 to position I. The advance of sequence switch 200 to position I8 disconnects ground from brush 234, releasing-the cut-off relay and freeing the substation 280 for subsequent calls- For the circuits and their functioning beyond the advance from the talking position, reference is made to the Berry Patent 1,658,829 above identified.

Turning now to Fig. 2, which discloses schematically a coin district selector, the talking circuit established with sequence switch I300 either in position I3 or position I4 extends from battery through the lower left winding of repeating coil I338 lower contact of relay i339, contacts of cam i3i0 through the winding of supervisory relay i351, lower back contact of relay 324, ring brush 325 of the line finder, through the subscribers substation, tip brush 328--A of the line finder, upper back-contact of relay 324, contact of cam i3l8, upper back contact of relay I339, upper left winding of repeating coil I338 to ground. Relay l3I'i operates in this circuit, in turn operating relay 323 in a circuit from battery through the winding of relay 323, front contact of relay i3I'I, contacts of cam I30! and ground. The outgoing end of the talking circuit extends from ground in the incoming selector as previously traced to terminal I05 and thence over brush I334, upper contacts of cam I335, upper right winding of repeating coil I338, winding of polarized relay I340, lower right winding of repeating coil I338, lower contacts of cam' I336, brush I331 to terminal I06 of the office selector and thence to battery as traced for the non-coin district selector.

The current flow in this circuit is such that relay I340 is operated. Relays I3I'I, 323 and i340 remain operated throughout the conversation. With relay I340 operated a circuit is closed from ground over the lower left and upper right contacts of cam I304, front contact of polarized relay i340, upper left and lower right contacts of cam I321 to interrupter I34I. When interrupter I34I closes its right contact, it operates relay 302A which looks under the control of relay I340 and closes a circuit over the left contact of interrupter I34I, right contact of relay 302-A and the contacts of cam I303 to the timing circuit which corresponds to Fig. 14 of the Hague patent above identified. When this timing circuit has started to function, ground is connected to the winding of relay 323 which operates and looks over its own right contact to the lower contacts of cam I304. Relay I340 also extends ground to the timing circuit as a signal that conversation has started.

When the conversation is completed, assuming that the called subscriber disconnects first, relay l I0 is released as previously described reversing the connection of relay I35 to the talking conductors and releasing relay I340. With relay 5340 released, ground is connected over the lower left and upper right contacts of cam i304, back contact of relay I340, outer left contact of relay 329, back contact of relay 33I--A to conductor 2 i. This conductor, which is individualto the district selector of Fig. 2, is connected through resistance 22 in multiple with conductor I0, and the conductors individual to other districts. As previously described, relays I2 and i3 operate intermittently under the control of interrupter i3. Relay I2 extends conductor 2i to the winding of relay I4 which operates, in turn operating relay i5 which closes a holding circuit for relay i4 under the control of conductor 2I. With relay i5 operated, when relay I8 operates, relay i1 is operated extending conductor 2I to conductor 23. The grounding of conductor 23 completes a circuit over the contacts of cam 24 through the right Winding of relay 32I-A to battery. Relay 32l-A operates in this circuit and locks in a circuit through its left winding and left front contact to ground over the right contacts of cam I333, closing a circuit from battery through the winding of sequence switch magnet i300, contacts of cam I3l4, right front contact of relay 32i-A, to ground over the lower contacts of cam I304. Sequence switch I300 advances to position I3 in this circuit. Theadvance of sequence switch i300 from position I5 opens the outgoing end of the talking circuit, permitting the office, incoming and final selectors to restore to normal as previously described. It also opens the incoming end of the talking circuit releasing relay 53H which in turn releases relay 323. When sequence switch I300 reaches position I0, the locking circuit of relay 32IA is opened and that relay releases, closing a circuit from cattery through the winding of sequence switch magnet i330, contacts of cam i322, back contact of relay 32EA to ground over the lower contacts of cam I333 advancing the sequence switch to position I'i. In this position the circuit of relay ISlJ is reclosed as well as the circuit of relay 323 to prevent the premature operation of relay 324. At the sametime, an overflow tone is transmitted to the calling subscriber over a circuit which can be traced from tone source 25 over the upper right and lower left contacts of cam I338 through the right windings of repeating coil I338, the winding of polarized relay I340 and the associated condenser, upper right and lower left contacts of cam I335, contacts of cam I3I3, right contacts of cam I301 to ground. This overflow tone is transmitted through the repeating coil E338 to the incoming talking circuit and the subscribers receiver to inform him that he should restore his receiver to the switchhook. When he does so, relays 13!! and 323 release. Since sequence switch I300 is now in position I1, relay 324 is operated to permit the coin circuit to function and to bring about the complete restoration of the circuit and selectors to normal. .These operations are described in detail in the Hague patent above identified.

The release control circuit of the lower part of Fig. 1 is, in general, used with a single district frame, relays l2 and I6 and interrupter l3 being common to all of the district selectors of the frame. Each of these relays carries four sets of contacts each of which is common toonefourth the districts mounted on the frame. Each contact of relay I2 operates a set of relays l4 and !5 which in combination with the corresponding contact of relay l6 operates a set of relays like relay H, to close an individual connection between the incoming and outgoing conductors H3 and 2D or 2! and 23 for each district on the frame. It may be noted that, although the probability of such an-occurrence is slight, if a second district selector grounds its incoming conductor ill at the time that relay II has been operated under the control of another district selector in the same group, the release function 'will take place immediately without waiting for a time interval measured by interrupter l3.

What is claimed is: 1. In a telephone system, a calling subscribers line, a called subscribers line, a selector switch, means including said selector switch for establishing a telephone connection between said call- V ers line, a called subscribers line, a selector I ing and called subscribers lines, means normally under the control of said calling subscriber's line for releasing said selector switch, means common to a plurality of said selector switches and controlled by said called subscriber's line for transmitting a release signal to said selector switch and means in said selector switch responsive to said signal for releasing said connection to free said called line.

2. In a telephone system, a calling subscribswitch, means including said selector switch for establishing a telephone connection between said calling and called subscribers lines, means normally under the control of said calling subscribers line for releasing said selector switch, and means common to a plurality of said selector switches and controlled by said called subscribers line for releasing said selector switch and said connection.

3. In a telephone system, a calling subscribers line, a called subscribers line, a selector switch, means including said selector switch for establishing a telephone connection between said calling and called subscribers lines, means normally under the control of said calling subscribers line for releasing said selector switch, timing means common to a plurality of said selector switches and controlled by said called subscribers line for closing a circuit individual to said selector switch, and means controlled by mally under the control of said calling subscribers line for releasing said selector switch, release control means common to a plurality of said selector switches, means under the control of said called subscriber for transmitting a sig- 7 nal to said release control means, and means in said release control means for extending said signal to said selector switch.

5. In a telephone system, a plurality of telephone connections each including a calling line, a called line and a selector switch, means normally under control of the calling line for releasing the associated selector switch, release control means common to said selector switches, means under the control of any one of said called lines for transmittinga signal to said release control means, timing means and means responsive to the operation of said timing means for causing said release control means to extend said signal to the selector switch with which said called line is connected and means for simultaneously extending sub-sequent signals from other called lines in the group to the corresponding selector switches.

6. In a telephone system, a calling subscribers line, a called subscriber's line, a selector switch, means including said selector switch for leasing said connection and signaling said calling subscriber. 7. In a telephone system, a calling line having an individual message register, a calling line having a coin box, a district selector serving said message register line, a district selector serving said coin box line, called lines, means including said selectors for establishing telephone connections between said calling and called lines, means normally under the control of said calling subscribers for releasing said switches, means common to said selector switch-es and controlled by a called subscriber for transmitting a signal to the selector employed in. the connection to said called line, means in said selector serving said message register line responsive to said signal for releasing said connection and said selector, and means in said selector serving said coin box line responsive to said signal for releasing said connection and signaling said calling line.

CHARLES W. KECKLER. ARTHUR RAYNSFORD.

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